Combined fertilizers versus dolomitic limestone: A comparative study from a forest habitat with Norway spruce

The research paper with character of case study deals with the influence of amelioration on soil as well as the Norway spruce nutrition and growth, with the focus on dolomitic limestone and combined fertilizer applications. The study was performed in the 7-year-old forest stand (Nízký Jeseník Mountains, Czech Republic, 100% Norway spruce, podzol, mor humus form, slightly undulated slope, 770 m a.s.l.). The soil properties (soil reaction, nutrient status, C/N ratio and cation exchange capacity), the plant nutrition, the plant biomass production and the health status were measured. Neither the expected significant increase in pH due to liming in the root zone nor the increase in calcium and magnesium in the soil was confirmed. In the dolomitic limestone treatment, the highest hydrolytic acidity reaching 260 mmol₊/kg, the worst development of assimilatory organs, the growth and health status of individuals were ascertained one year after the usage. The application of combined fertilizers resulted in the highest response in the needle biomass production (0.35 g/100 needles compared to less than 0.30 g/100 needles in the dolomitic limestone treatment), in the potassium and phosphorus nutrition status (suboptimal 4–4.5% of potassium in dolomitic limestone and the control treatment compared to optimal 5.5–7.5% in the combined fertilizers treatments) and simultaneously to the optimization of the health status. Specifically, in forest stands, the effect of dolomitic limestone is rather overestimated and furthermore, chemical amelioration requires the detailed knowledge of the forest site.